Case Study: FMR 230 Sludge Digester Level

The Micropilot M FMR 230 has been selected as the most reliable instrument in the measurement of the sludge digester level the waste water industry.

Global specialist in water and wastewater operations, products and services serving mainly in the south of England.

MMA is used in many established products, such as paints, plastics, dyes, pharmaceuticals, and in the automotive industry.

In the sludge digester, enzymes and micro-organisms work under anoxic conditions to degrade the organic solids from the primary and activated sludge mixture. As the amount of sludge is reduced, water and gas, mainly methane and carbon dioxide, are produced, leaving behind the inorganic sludge. The sludge is circulated around the digester at temperatures up to 122°F (50°C). This causes a very humid atmosphere with high levels of condensation.

Ultrasonics have been used in these applications previously, but suffered from signal attenuation due to the high moisture levels.

The FMR 230 with a 6” horn was selected for its ability to measure very disturbed surfaces even with high condensation levels present. The measurement was also unaffected by the methane gas produced in the digester, resulting in maintained accuracy during every cycle.

The unit has performed well, considering the harsh working conditions. Following commissioning of the FMR 230, it only requried a small increase in blocking distance to ensure continued reliability.